{"release":{"id":"DR1","released_on":"2026-08-21","doi":null,"url":"https://spacecatalog.org/releases#dr1"},"epoch":{"requested":"now","label":"J2026.668","julian_year":2026.668,"time":"2026-09-01T19:40:26.275Z","years_from_j2000":26.668,"frame":"date","applied":"Proper motion, then precession and nutation. The catalogued J2000 position is carried along the great circle the object's own published motion puts it on, at a constant velocity, and the result is referred to the true equator and equinox of this instant. Those are separate things: the motion moves the object, and the rotation turns the grid under it by about fifty arcseconds a year, with nutation adding up to another seventeen.","excluded":"Parallax, the radial-velocity perspective term, aberration and refraction; each is below the accuracy of the catalogued positions themselves. An object with no published proper motion comes back where the catalogue has it rather than at a fabricated zero, and says so with a null pm_ra_mas_yr. A body with no fixed position is not propagated at all — its place comes from an ephemeris, which is what /api/v1/visible answers with."},"slug":"ngc-181","name":"NGC 181","class":"lenticular_galaxy_s0_a","category":"galaxy","object_type":"Lenticular galaxy S0-a","mag":15.53,"mag_band":"B","abs_mag":null,"abs_mag_band":null,"distance_ly":246003370.17777142,"distance_method":"redshift (CMB frame), flat ΛCDM with H0 = 70 km/s/Mpc","ra_deg":9.596708333333334,"dec_deg":29.472583333333333,"epoch_ra_deg":9.953792,"epoch_dec_deg":29.620271,"epoch_moved_arcsec":null,"pm_ra_mas_yr":null,"pm_dec_mas_yr":null,"orbits":null,"semi_major_axis_km":null,"periapsis_km":null,"mass_kg":null,"mass_msun":null,"constellation":"Andromeda","discovered":"1883","featured":false,"url":"https://spacecatalog.org/object/ngc-181","radius_km":null,"radius_kind":null,"data_quality":null,"description":null,"properties":{"b_mag":15.53,"h_mag":11.37,"j_mag":12.12,"k_mag":11.01,"redshift":0.018466,"hubble_type":"S0-a","wikidata_id":"Q1035680","redshift_cmb":0.01738213526963528,"discovered_by":"Édouard Stephan","ngc_type_code":"G","uncertainties":{"distance_ly":[17285587.365100328,17285587.365100328]},"major_axis_arcmin":0.86,"minor_axis_arcmin":0.25,"wikipedia_article":"NGC 181","position_angle_deg":152,"surface_brightness":23.8,"radial_velocity_km_s":5485},"designations":[{"catalog":"2MASX","designation":"2MASX J00382319+2928214"},{"catalog":"IRAS","designation":"IRAS F00356+2911"},{"catalog":"LEDA","designation":"LEDA 2287"},{"catalog":"MCG","designation":"MCG +05-02-032"},{"catalog":"NGC","designation":"NGC 181"},{"catalog":"PGC","designation":"PGC 2287"}],"source":{"id":"openngc","name":"OpenNGC","url":"https://github.com/mattiaverga/OpenNGC","license":"CC-BY-SA-4.0"},"updated_at":"2026-08-30T09:56:50.739Z","attribution":"Data from SpaceCatalog.org. Individual records carry their source and license in `source`; attribution is required for CC-BY and CC-BY-SA rows."}